441 



4. Apherusa borealis (Boeck). 



(PI. 155, fig. 2). 

 Halircujcs borealis, Boeck, Arnph. bor. & arct. p. 116. 



Body somewhat more elongated than in A. lispinosa, and having, as 

 in that species, the 2 anterior segments of metasome produced dorsally to 

 posteriorly pointing projections, which however are somewhat less prominent. 

 Cephalon comparatively smaller than in the said species, not even attaining 

 the length of the first 2 segments of mesosome combined, rostral projection 

 very slight, lateral corners obtusely rounded at the tip, poatantennal ones 

 but little produced. Anterior pairs of coxal plates about as deep as the 

 body; 1st pair scarcely at all expanded distally, and, like the 2 succeeding 

 pairs, rounded quadrangular in form; 4th pair of somewhat unusual shape, 

 being obliquely rounded, and scarcely widening distally. Last pair of epimeral 

 plates of metasome but very little expanded, lateral corners terminating in 

 a short and blunt point, posterior edge evenly curved and perfectly smooth. 

 Eyes comparatively small, and of rounded form Superior antennae in female 

 considerably exceeding 1 /3 of the length of the body, 1st joint of the peduncle 

 equalling in length the other 2 combined, flagellum about 3 times as long as 

 the peduncle, and composed of 22 articulations. Inferior antennse, as usual, 

 somewhat longer than the superior, and having the last 2 joints of the 

 peduncle about equal-sized. Gnathopoda somewhat less slender than in the 

 preceding species, and having the carpus comparatively shorter and broader, 

 propodos exceeding the carpus in length, and of the usual narrow oblong 

 form. Pereiopoda comparatively more strongly built than in that species, 

 with the meral joint rather broad in proportion to its length, and the dactylus 

 very strong; basal joint of penultimate and antepenultimate pairs rounded 

 oval in form, that of last pair much larger and more oblong in form, posterior 

 edge in all 3 pairs quite smooth and evenly curved. Last pair of uropoda 

 comparatively less elongated than in A. lispinosa, with the rami but little 

 longer than the basal part, and regularly lanceolate in form, opposite edges 

 not serrated, marginal spines few in number. Telson triangular in shape, 

 scarcely twice as long as it is broad at the base, tip simple, pointed. Colour 

 in the living state of the animal not yet stated. Length of adult female 

 scarcely attaining 8 mm. 



Remarks. This species, established by Boeck, is nearly allied to 

 A. bispinosa, though easily distinguishable by the small size of the eyes and 

 the very different shape of the last pair of epimeral plates of metasome. 



